Fluorescence Detection and Discrimination of ss- and ds-DNA with a Water Soluble Oligopyrene Derivative

A novel water-soluble cationic conjugated oligopyrene derivative, oligo(N1,N1,N1,N4,N4,N4-hexamethyl-2-(4-(pyren-1-yl) butane-1,4-diaminium bromide) (OHPBDB), was synthesized by a combination of chemical and electrochemical synthesis techniques. Each oligomer chain has five pyrene derivative repeating units and brings 10 positive charges. OHPBDB showed high and rapid fluorescence quenching in aqueous media upon addition of trace amounts of single-stranded (ss) and double-stranded (ds) DNA. The Stern-Volmer constants for ss- and ds-DNA were measured to be as high as 1.3 × 108 mol−1·L and 1.2 × 108 mol−1·L, respectively. On the other hand, distinct fluorescence enhancement of OHPBDB upon addition of large amount of ss-DNA or ds-DNA was observed. Furthermore, ss-DNA showed much stronger fluorescence enhancement than that of ds-DNA, thus yielding a clear and simple signal useful for the discrimination between ss- and ds-DNA in aqueous media

Simulation analysis of underwater structure based on local cylindrical acoustic holography

The local cylindrical acoustic holography technology is introduced, and its application in identifying and locating the column is introduced. The implementation algorithm of local cylindrical holographic reconstruction is given. In engineering operations, columnar sound sources such as electric motors, water pipes, and underwater structures are common noise sources in engineering. Therefore, this paper is of great significance for the location identification and control of such sound sources. The simulation results show that the proposed local cylindrical acoustic holography algorithm is useful to identify the noise source and reconstruct the sound field correctly

Electrosynthesis of oligo(methoxyl pyrene) for turn-on fluorescence detection of volatile aromatic compounds

highly fluorescent conjugated oligomer, oligo(1-methoxyl pyrene) (OMOPr), was synthesized via electrochemical polymerization and its structure was studied by UV-vis spectroscopy, MALDI-TOF mass spectroscopy and ab initio calculation. The organic solutions of OMOPr emit strong blue lights and show solvatochromic effect, while these fluorescence emissions are quenched upon chain aggregation in its dry films. On the basis of these phenomena, a turn-on fluorescence sensor was fabricated and it can be used for detecting volatile aromatic compounds (VACs)

Gas Sensors Based on Conducting Polymers

The gas sensors fabricated by using conducting polymers such as polyaniline (PAni), polypyrrole (PPy) and poly (3,4-ethylenedioxythiophene) (PEDOT) as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review